Java-小项目-零钱通

零钱通

【面向过程做法 procedure-oriented】

化繁为简：

1. 先完成显示菜单，并可以选择

2. 完成零钱通明细
   （学习）老韩思路：
   （1）可以把收益入账和消费，保存到数组中（但目前学到的数组是定长的）
   （2）可以使用对象
   （3）可以使用String拼接

3. 完成收益入账，完成功能驱动程序员增加新的变化的代码
   （1）要接收收益入账的金额，并更新余额
   （2）拼接好字符串
   （3）找到时间如何输出，并且修改其输出格式

4. 完成消费
   跟3差不多

建议一段代码，完成一个小功能，尽量不要混在一起

public class Change {
	public static void main(String[] args) {
		boolean loop = true;
		Scanner scanner = new Scanner(System.in);
		String key = "";  //菜单选择
		String details = "------------零 钱 通 明 细------------";
		String place = "";

    double money = 0; //收益入账金额或消费金额
    double balance = 0; //余额
    Date date = null; //日期
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh-mm"); //用于日期格式化

    do {
        System.out.println("\n" + "------------零 钱 通 菜 单------------");
        System.out.println("\t\t\t1 零钱通明细");
        System.out.println("\t\t\t2 收益  入账");
        System.out.println("\t\t\t3 消     费");
        System.out.println("\t\t\t4 退     出");
        System.out.print("请选择(1-4): ");

        key = scanner.next();

        switch (key){
            case "1":
                System.out.println(details);
                break;
            case "2":
                System.out.print("收益入账金额:");
                money = scanner.nextDouble();
                if(money<=0){
                    System.out.println("输入有误，请重新记录收益入账！");
                    break;
                }
                balance += money;
                date = new Date(); //获取当前日期
                details +="\n" + "收益入账" + "\t+" + money + "\t" + sdf.format(date) + "\t" + "余额:" + balance;
                break;
            case "3":
                System.out.print("消费说明:");
                place = scanner.next();

                System.out.print("消费金额:");
                money = scanner.nextDouble();
                if(money<=0){
                    System.out.println("输入有误，请重新记录消费！");
                    break;
                }
                balance -= money;

                details +="\n" + place + "\t-" + money + "\t" + sdf.format(date) + "\t" + "余额:" + balance;
                break;
            case "4":
                String choice = "";
                while (true){
                    System.out.println("------------请确认是否退出"+"------------"+ "\n" + "输入y确认退出" + "\t" + "输入n取消退出");
                    choice = scanner.next();
                    if(choice.equals("y") || choice.equals("n"))
                        break;
                }
                if (choice.equals("y")){
                    loop = false;
                }
                break;
            default:
                System.out.println("输入有误，请输入1-4的数字");
        }
    }while (loop);
    System.out.println("*******已退出零钱通*******");
}

}

---

【面向对象做法 Object-Oriented】

变量作为属性，功能作为方法封装起来

public class ChangeOOP {
	boolean loop = true;
	Scanner scanner = new Scanner(System.in);
	String key = "";  //菜单选择
	String details = "------------零 钱 通 明 细------------";
	String place = "";

double money = 0; //收益入账金额或消费金额
double balance = 0; //余额
Date date = null; //日期
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh-mm"); //用于日期格式化

public void mainMenu(){
    do {
        System.out.println("\n" + "------------零 钱 通 菜 单------------");
        System.out.println("\t\t\t1 零钱通明细");
        System.out.println("\t\t\t2 收益  入账");
        System.out.println("\t\t\t3 消     费");
        System.out.println("\t\t\t4 退     出");
        System.out.print("请选择(1-4): ");

        key = scanner.next();

        switch (key){
            case "1":
                this.showDetail();
                break;
            case "2":
                this.income();
                break;
            case "3":
                this.pay();
                break;
            case "4":
                this.exit();
                break;
            default:
                System.out.println("输入有误，请输入1-4的数字");
        }
    }while (loop);
    System.out.println("*******已退出零钱通*******");
}
public void showDetail(){
    System.out.println(details);
}
public void income(){
    System.out.print("收益入账金额:");
    money = scanner.nextDouble();
    if(money<=0){
        System.out.println("输入有误，请重新记录收益入账！");
        return;
    }
    balance += money;
    date = new Date(); //获取当前日期
    details +="\n" + "收益入账" + "\t+" + money + "\t" + sdf.format(date) + "\t" + "余额:" + balance;
}
public void pay(){
    System.out.print("消费说明:");
    place = scanner.next();

    System.out.print("消费金额:");
    money = scanner.nextDouble();
    if(money<=0 || money>balance){
        System.out.println("输入有误，请重新记录消费！");
        return;
    }
    balance -= money;

    details +="\n" + place + "\t-" + money + "\t" + sdf.format(date) + "\t" + "余额:" + balance;
}
public void exit(){
    String choice = "";
    while (true){
        System.out.println("------------请确认是否退出"+"------------"+ "\n" + "输入y确认退出" + "\t" + "输入n取消退出");
        choice = scanner.next();
        if(choice.equals("y") || choice.equals("n"))
            break;
    }
    if (choice.equals("y")){
        loop = false;
    }
}

}